2.07.2011

Who would have known something so innocuous as cheese would be breaking so many boundaries. I talked last year about the cheese wheel that went into space. Now some research in the Journal of Food Engineering offers some methods for measuring cheese composition. You know an article that begins The cheese industry demands... is going to be good. I picture them to be a 1950s-esque men in black kind of organization setting the requirements for cheese.

But food composition is serious business, after all Taco Bell is being sued for its beef content in its tacos. Using ultrasonics to detect food composition has been around and has advantages over traditional methods. Mostly you don't have to destroy the food you're testing. In this case the experimenters were analyzing eight brands of cheese. They extracted cylinders of the cheese samples and used a pair of narrow band ultrasonic transducers. These devices generate sound waves in the ultrasonic range and in this case send them at the cheese. They rounded out their test equipment with a pulser receiver and a good old oscilloscope.

They then measured the ultrasound velocity of the samples at various temperatures. The receiver measured the time it took the wave to travel through the cheese, six trials each, and they had the cylinders measured to an accuracy of 0.01 mm. What maybe was expected was that the velocity would be based on the fat and water content of the cheeses. The fat behaving differently at various temperatures was what led to velocity measurements at different temperatures.

What they found was the structure of the cheese mattered a lot. The equations for modelling wave propagation based on dairy fat could change based on how the manufacturer made their cheese and the texture of the cheese even if the fat and water composition was very similar. The experimenters also made their own cheese blends using a vacuum to remove extraneous air and found their predictions fared better in this case because the differences in cheese structure and manufacturing didn't have as much of an effect.

So sound waves to test food? Probably not too far around the corner. It's easy to think of industrial applications where this would simplify your quality process or even better a way of making government food agencies much more productive with their limited resources. But there would have to be a lot of development and specialization to get it to be accurate.